Indoor Team Sports Research Articles

Identifying the Qualities of Attention and the Attentional Style in Indoor Team Sports: A Gender Comparison.

Attention is an essential psychological component in sports games, which conditions sports success. The purpose of this study was to identify the attention style (internal or external) and the weight of attention qualities depending on the practiced team sport (basketball, volleyball, or handball) and gender (female or male), in athletes aged 15-18. A total of 177 active athletes (87 female (mean age ± standard deviation: 16.07 ± 0.94 years) and 90 male (mean age ± standard deviation: 15.96 ± 0.82 years)) were involved in the study, including 62 handball players (28 female and 34 male), 58 volleyball players (30 female and 28 male) and 57 basketball players (29 female and 28 male). In the study, two questionnaires were applied: one implemented to identify the attentive style with the two dimensions internal and external (standardized), called questionnaire for the assessment of attentional style in athletes (QASA), and one designed by us, called questionnaire to identify the weights of attention qualities according to the characteristics of the practiced sport (QAQCS), aiming to identify the most relevant quality of attention, depending on the practiced sport. Cronbach's alpha for both questionnaires was between 0.701 and 0.855. The results recorded in the present study reveal a variation in the attentional style between the groups of athletes and between genders. The results of the study highlight that in handball, girls have a predominantly external style with a total of 10.213 points; in boys' handball, the predominant focus of attention is internal with a total score of 9.087 points. Girls' volleyball focus of attention is predominantly external, with 8.999 points; in boys' volleyball, the attention style is internal, registering a score of 9.713 points. In girls' basketball, the predominant focus of attention is internal, with a total score of 8.516 points; in boys' basketball, the external attention style is predominant, with 9.213 points. Looking at the weight of attention qualities, it was found that the most relevant for girls is concentration and mobility for handball players, stability was identified in volleyball, and distributiveness in basketball. In boys' handball teams, mobility is the most essential, just like in basketball, and in volleyball it was found that stability has the biggest impact. ANOVA analysis highlighted statistically significant differences between groups of sports games by gender category, at both subscales of (QASA), as well as QAQCS, p < 0.05. The results of our study highlight differences between the attentional styles and their qualities in relation to the gender and the specific sport played, which determines differentiated approaches to these psychological components.

Evolution of Vitamin D Status and Vitamin D Receptor Gene Expression Among Professional Handball Athletes During a Competitive Period. Relationship with Body Composition, Calcium, Magnesium and Phosphorous.

A generalized risk of vitamin D deficiency exists worldwide affecting also professional and elite athletes. This study assesses the evolution of vitamin D status and vitamin D receptor (VDR) gene expression and their relationship with body composition, calcium (Ca), magnesium (Mg) and phosphorous (P) among professional handball athletes during a competitive period. A total of 26 male subjects were recruited: 13 professional handball athletes and 13 non-athlete controls. An observational follow-up study was conducted in 2 time points over a 16-week period. Nutritional intake, body composition, and routinary biochemical parameters were measured via 24-hours recall, bioimpedance and enzyme immunoassay, respectively. Ca and Mg were measured by flame atomic absorption spectrophotometry and P was determined with the colorimetric method of Fiske-Subbarow. 25-hydroxyvitamin-D (25(OH)D) levels and its forms (i.e., 25(OH)D3 and 25(OH)D2) were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS), whereas VDR gene expression was measured by quantitative real time-polymerase chain reaction (qRT-PCR). A total of 54% of the athletes showed deficient vitamin D status. Moreover, a prevalence of insufficient vitamin D status in handball players affected 46% at baseline, reaching 61% after 16 weeks. Vitamin D showed no evolution during the competitive period and no differences between groups were observed (all p ≥ 0.05). Handball players increased the VDR expression, enhanced body composition, Ca and Mg levels at 16-weeks follow-up (all p < 0.05). VDR gene expression was positively related with body mass and body mass index at follow-up in athletes (all p ≤ 0.038; r ≥ 0.579) and with Ca at baseline in controls (p = 0.026; r = 0.648). Finally, 25(OH)D2 form was directly associated with P in athletes at 16 weeks of study (p = 0.034; r = 0.588). Players of indoor team sports such as handball would be a population at risk of vitamin D deficiency. The 16-weeks competition improved VDR gene expression, body composition, Ca and Mg levels. The associations observed between VDR gene expression and the variables of the study evidenced the importance of this receptor as a marker involved in health status in handball athletes despite vitamin D - although in a deficient status -, Ca, Mg and P showed no remarkable changes during the competition period.

Inter-system and inter-unit reliability of Polar Team Pro and WIMU PRO devices during external load measurements indoors

The aim was to examine inter-system and inter-unit reliability of both WIMU PRO (UWB) and Polar Team Pro devices in measuring indoor sport-specific movements. Seventeen active and healthy adults (age: 21.4 ± 5.2 years; height 170.3 ± 8.2 cm; body mass: 71.2 ± 4.5 kg) completed one repetition of an indoor team sport circuit (i.e. accelerations, decelerations, change of direction, jumps and arc runs). Participants carried two 10-Hz Polar Team Pro GPS and wore two 20-Hz GPS (UWB) WIMU PRO chest- and back-mounted devices, respectively. Distance (absolute, relative and in different speed thresholds), mean and peak speed, accelerations and decelerations at different intensities and jumps were recorded. A repeated-measures two-way analysis of variance and ICC and CV were utilised. There was a significant ( p ≤ 0.001) main effect of the system for all variables except the total distance, mean speed and distance covered during low- and high-intensity running. There were significant differences ( p &lt; 0.05) between the two Polar Team Pro units for all external load variables except for distance covered during submaximal speed, moderate-intensity accelerations (ACC), and moderate-intensity and total decelerations (DCC). No significant differences ( p &gt; 0.05) between the two WIMU PRO units were detected. Poor inter-system reliability was ascertained, with inter-unit reliability being moderate-excellent for most variables of both systems.

Monitoring of internal and external loads to interpret acute and chronic fatigue in indoor team sports: A systematic review

The aims of this study were: (1) to analyze how the periodization of workloads can induce states of accumulated fatigue in the short, medium and long term in indoor team sports and (2) to identify these periods of fatigue through the interpretation internal and external performance variables. This systematic review was carried out under PRISMA guidelines. The Web of Science, PubMed and Scopus databases were searched for relevant published studies between 1st January 2010 and 25th April 2021. The STROBE scale and MINORS checklist were used to assess the reporting and methodological risk of bias, respectively. Of the 2219 studies initially identified, 20 were selected for a full review. The main conclusions were that a periodic and integrative evaluation of monitoring variables of a different nature is needed to identify states of fatigue accurately and rigorously. The end of the preparatory periods (PPs) and the second phase of the competitive periods (CPs) seem to be the most exhausting moments of the season (high values of RPE, CK, LDH, and oxidative stress markers, and decrease in the T/C ratio). Specifically, congested weeks promote the development of high levels of acute and subacute fatigue (high levels of DOMS and fatigue along with low levels of RPE). Therefore, it is recommended to extend the duration of the preseason and the implementation of more active recovery days during congested weeks, in order to improve resistance to acute and subacute fatigue, and therefore avoid reaching a state of overtraining.

A Moderated Mediation Analysis of the Effects of the COVID-19 Pandemic on Well-Being and Sport Readiness of Italian Team Sports Players: The Role of Perceived Safety of the Training Environment.

Background: The protective restrictions (e.g., lockdowns, quarantines, social and physical distancing) consequent to the global pandemic caused by COVID-19 posited new challenges to athletes practicing competitive team sports. This study aimed to gain an understanding of the impact of the ongoing COVID-19 pandemic on the well-being and sports readiness to train and to compete of competitive female and male athletes practicing outdoor (i.e., rugby, soccer) and indoor (i.e., volleyball, basketball) team sports who were active during the Italian first and second waves of COVID-19. Methods: An online survey assessing demographic characteristics, perceived safety of the training environment, COVID-19 risk, fear of COVID-19, well-being, and sport (training and competition) readiness was administered to 619 team sports players. We examined differences by gender, previous COVID-19 experience, and team sport setting (i.e., outdoor vs. indoor). A moderated mediation analysis was conducted to assess the impact of perceived COVID-19 risk and fear of COVID-19 on athletes’ well-being and sports readiness, using perceived safety of the training environment as a mediator and gender and sport setting as moderators. Results: Indoor team sports and female athletes showed higher perceived COVID-19 risk, while athletes with no-COVID-19 experience reported higher fear of COVID-19. Perceived COVID-19 risk (directly and via perceived safety of the training environment) and fear of COVID-19 were negatively associated with athletes’ well-being and sports readiness. Conclusions: This study highlighted an understanding of the psychological implications of the COVID-19 pandemic, emphasizing the role of the perceived safety of the training environment on athletes’ well-being and sports readiness. Future studies may advance safety-based interventions to promote well-being and a safer return to sport.

The relationship between internal and external loads as a tool to monitor physical fitness status of team sport athletes: a systematic review.

The efficiency index (Effindex) combines internal and external loads, and it has been considered a promising tool to evaluate physical fitness status. However, its real applicability and limitations have not been elucidated yet. To examine and discuss the findings from studies that used Effindex as a tool for the evaluation of physical fitness status in team sports. A systematic search was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The databases conferred were PubMed, Scopus, Web of Science, SPORTDiscus, MEDLINE and CINAHL. The articles selected were published up to March 2021. Fourteen articles were included after meeting the inclusion criteria. A wide variety of combinations of external and internal loading parameters to calculate Effindex were found. The pooled sample included 349 male participants (23 ± 3 years). Fifty-nine percent of the sample were soccer players, 20% rugby players, 10% Australian football players, 7% hurling players, and 4% basketball players. Most Effindex calculations used total distance (TD) divided by heart rate derived parameters. However, recent studies have suggested the use of accelerations as the external load parameter. Effindex is a simple and powerful tool for the evaluation of physical fitness status in team sports athletes. The disparity of external and internal loading parameters used to calculate Effindex may affect its sensitivity to detect changes in fitness status in different team sport settings. More studies with indoor team sports and female athletes are warranted.

Accuracy and reliability of Sage Analytics tracking system based on UWB technology for indoor team sports

ABSTRACT Reliability and accuracy of Sage Analytics system for team games is currently unknown. Therefore, the aim of this study is to assess validity and reliability of SAGE Analytics during prescribed movements and specific basketball movements. Eighteen male basketball players completed straight line movements (28 m), zig zag movements (20 m) by walking, jogging and sprinting, and 4 on 4 small-sided game measured by Sage and VideoManualMotionTracker 1.0. Results: System seems to underestimate distance in protocols with changes of directions (2.09–3.49%) and slightly overestimate straight locomotion (1.91–2.38%). At the same time change of direction measurement protocol showed lower error than straight measurement protocol. System showed high reliability (r = 0.985, SEM = 1.42 m). Sage Analytics system was confirmed as a sufficient accurate and reliable tool to determine total distance.

Associations Between Two Athlete Monitoring Systems Used To Quantify External Training Loads In Basketball Players

Quantifying external training load (eTL), referred to as the biomechanical load during training, is becoming increasingly popular for team sport in an effort to manage fatigue, optimize performance, and guide return-to-play protocols following injury. During indoor team sport play, eTL can be measured via Inertial Measurement Units (IMUs) which incorporate accelerometers, gyroscopes, and a magnetometer to characterize an athlete’s movement signature, while Indoor Positioning Systems (IPS) are also common, which use Ultra-wideband (UWB) to detect player positioning and their subsequent movements. PURPOSE: The purpose of this study was to assess the association between a commercially available IMU and IPS used to monitor eTL in team sport. METHODS: A retrospective analysis was performed on 13 elite male NCAA Division 1 basketball players from three practices during the off-season training phase. A Pearson’s correlation was used to examine the association between the Distance traveled during practice captured by IPS system compared to PlayerLoad (PL), PlayerLoad per Minute (PL/Min), 2-Dimensional PlayerLoad (PL2D), 1-Dimensional PlayerLoad Forward (PL1D-FWD), Side (PL1D-SIDE), and Up (PL1D-UP) captured from the Catapult Sport IMU. RESULTS: There were significant (p ≤ 0.001) positive correlations between Distance and PL (r=0.891), PL/Min (r=0.891), PL2D (r=0.863), PL1D-FWD (r=0.799), PL1D-SIDE (r=0.879), and PL1D-UP (r=0.887) during Practice 1. Practice 2 revealed significant (p ≤ 0.001) positive correlations between Distance and PL (r=0.947), PL/Min (r=0.947), PL2D (r=0.901), PL1D-FWD (r=0.819), PL1D-SIDE (r=0.944), and PL1D-UP (r=0.972), while Practice 3 also displayed significant (p ≤ 0.001) positive correlations between Distance and PL (r=0.858), PL/Min (r=0.872), PL2D (r=0.809), PL1D-FWD (r=0.810), PL1D-SIDE (r=0.761), and PL1D-UP (r=0.891). CONCLUSION: These data suggest a strong association between parameters captured by the two systems used to monitor eTL, however coaches and performance practitioners should be aware that each system may potentially provide unique information used to monitor and track eTL of athletes during basketball play.

Validation of Wearable Sensors during Team Sport-Specific Movements in Indoor Environments.

The aim of this study was to determine possible influences, including data processing and sport-specific demands, on the validity of acceleration measures by an inertial measurement unit (IMU) in indoor environments. IMU outputs were compared to a three-dimensional (3D) motion analysis (MA) system and processed with two sensor fusion algorithms (Kalman filter, KF; Complementary filter, CF) at temporal resolutions of 100, 10, and 5 Hz. Athletes performed six team sport-specific movements whilst wearing a single IMU. Mean and peak acceleration magnitudes were analyzed. Over all trials (n = 1093), KF data overestimated MA resultant acceleration by 0.42 ± 0.31 m∙s−2 for mean and 4.18 ± 3.68 m∙s−2 for peak values, while CF processing showed errors of up to 0.57 ± 0.41 m∙s−2 and −2.31 ± 2.25 m∙s−2, respectively. Resampling to 5 Hz decreased the absolute error by about 14% for mean and 56% for peak values. Still, higher acceleration magnitudes led to a large increase in error. These results indicate that IMUs can be used for assessing accelerations in indoor team sports with acceptable means. Application of a CF and resampling to 5 Hz is recommended. High-acceleration magnitudes impair validity to a large degree and should be interpreted with caution.

The Yo-Yo Intermittent Endurance Level 2 Test: Reliability of Performance Scores, Physiological Responses and Overload Characteristics in Competitive Soccer, Basketball and Volleyball Players.

The purpose of this study was to evaluate the reliability and reproducibility of the physiological and overload features of the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2) in competitive male soccer (n = 20), basketball (n = 11), and volleyball players (n = 10). The participants completed Yo-Yo IE2 tests on three separate occasions with assessment of performance, heart rate, running speed, accelerations, decelerations and body load using GPS instrumentation. The intra-class correlation coefficient index, confidence intervals and coefficients of variation were calculated to assess the reliability of the test. Intra-class correlation coefficients for test-retest trials in the total sample ranged from large to nearly perfect (total distance: 0.896; mean speed: 0.535; maximum speed: 0.715; mean HR: 0.876; maximum HR: 0.866; body load: 0.865). The coefficients of variation for distance, mean speed, HR response, as well as acceleration and deceleration scores for test-retest trials ranged from 1.2 to 12.5% with no differences observed among particular sport disciplines. The CV for shuttles performed ranged from 4.4 to 5.5% in all sports. Similar results were obtained for the three different categories of players tested. These results suggest that the Yo-Yo IE2 test appears to be a reliable alternative for evaluating the ability to perform intermittent high-intensity running in different outdoor and indoor team sports. Players may need one or two familiarization tests to ensure valid assessment of intermittent endurance capacity. It appears that the Yo-Yo IE2 test incorporates accelerations and decelerations in a consistent and reproducible fashion.

Validity of the Catapult ClearSky T6 Local Positioning System for Team Sports Specific Drills, in Indoor Conditions.

Aim: The aim of the present study was to determine the validity of position, distance traveled and instantaneous speed of team sport players as measured by a commercially available local positioning system (LPS) during indoor use. In addition, the study investigated how the placement of the field of play relative to the anchor nodes and walls of the building affected the validity of the system.Method: The LPS (Catapult ClearSky T6, Catapult Sports, Australia) and the reference system [Qualisys Oqus, Qualisys AB, Sweden, (infra-red camera system)] were installed around the field of play to capture the athletes' motion. Athletes completed five tasks, all designed to imitate team-sports movements. The same protocol was completed in two sessions, one with an assumed optimal geometrical setup of the LPS (optimal condition), and once with a sub-optimal geometrical setup of the LPS (sub-optimal condition). Raw two-dimensional position data were extracted from both the LPS and the reference system for accuracy assessment. Position, distance and speed were compared.Results: The mean difference between the LPS and reference system for all position estimations was 0.21 ± 0.13 m (n = 30,166) in the optimal setup, and 1.79 ± 7.61 m (n = 22,799) in the sub-optimal setup. The average difference in distance was below 2% for all tasks in the optimal condition, while it was below 30% in the sub-optimal condition. Instantaneous speed showed the largest differences between the LPS and reference system of all variables, both in the optimal (≥35%) and sub-optimal condition (≥74%). The differences between the LPS and reference system in instantaneous speed were speed dependent, showing increased differences with increasing speed.Discussion: Measures of position, distance, and average speed from the LPS show low errors, and can be used confidently in time-motion analyses for indoor team sports. The calculation of instantaneous speed from LPS raw data is not valid. To enhance instantaneous speed calculation the application of appropriate filtering techniques to enhance the validity of such data should be investigated. For all measures, the placement of anchor nodes and the field of play relative to the walls of the building influence LPS output to a large degree.

Player Monitoring in Indoor Team Sports: Concurrent Validity of Inertial Measurement Units to Quantify Average and Peak Acceleration Values.

The increasing interest in assessing physical demands in team sports has led to the development of multiple sports related monitoring systems. Due to technical limitations, these systems primarily could be applied to outdoor sports, whereas an equivalent indoor locomotion analysis is not established yet. Technological development of inertial measurement units (IMU) broadens the possibilities for player monitoring and enables the quantification of locomotor movements in indoor environments. The aim of the current study was to validate an IMU measuring by determining average and peak human acceleration under indoor conditions in team sport specific movements. Data of a single wearable tracking device including an IMU (Optimeye S5, Catapult Sports, Melbourne, Australia) were compared to the results of a 3D motion analysis (MA) system (Vicon Motion Systems, Oxford, UK) during selected standardized movement simulations in an indoor laboratory (n = 56). A low-pass filtering method for gravity correction (LF) and two sensor fusion algorithms for orientation estimation [Complementary Filter (CF), Kalman-Filter (KF)] were implemented and compared with MA system data. Significant differences (p < 0.05) were found between LF and MA data but not between sensor fusion algorithms and MA. Higher precision and lower relative errors were found for CF (RMSE = 0.05; CV = 2.6%) and KF (RMSE = 0.15; CV = 3.8%) both compared to the LF method (RMSE = 1.14; CV = 47.6%) regarding the magnitude of the resulting vector and strongly emphasize the implementation of orientation estimation to accurately describe human acceleration. Comparing both sensor fusion algorithms, CF revealed slightly lower errors than KF and additionally provided valuable information about positive and negative acceleration values in all three movement planes with moderate to good validity (CV = 3.9 – 17.8%). Compared to x- and y-axis superior results were found for the z-axis. These findings demonstrate that IMU-based wearable tracking devices can successfully be applied for athlete monitoring in indoor team sports and provide potential to accurately quantify accelerations and decelerations in all three orthogonal axes with acceptable validity. An increase in accuracy taking magnetometers in account should be specifically pursued by future research.

Injuries during the international floorball tournaments from 2012 to 2015

BackgroundFloorball is a running indoor team sport that has growing popularity worldwide. Some prospective studies have investigated injuries in national floorball leagues, but such studies at the international level are...

The intensity and energy expenditure of exertions, restitution speed, and rate of perceived exertion after tournament matches in Polish futsal players

PurposeFutsal is a very dynamic indoor team sport. Like in soccer, futsal players perform a number of efforts of different intensity during a match. In each match there are a few return substitutions to allow players to have some rest. The aim of the study was to assess the intensity and energy expenditure of single efforts and the dynamics of restitution after the efforts during successive futsal matches.MethodsThe study consisted in measuring the players’ (&lt;i&gt;n&lt;/i&gt; = 11) heart rate (HR) during four matches: A, B, C, D. The HR measurement started during a pre-match warm-up and ended 5 min after the match.ResultsThe highest intensity of single efforts was noticed in match A. It equalled 90.22 ± 4.90% HR&lt;sub&gt;max&lt;/sub&gt; and it was the highest in comparison with other matches (&lt;i&gt;p&lt;/i&gt; &lt; 0.05). The energy expenditure of efforts performed by players in the matches was 395.11 ± 118.70 kcal. The mean energy expenditure of a single effort was 16.33 ± 5.36 kcal/min. The highest energy expenditure was registered in match A, and it equalled 17.31 ± 4.71 kcal/min during a single effort on the pitch after a return substitution.ConclusionsThe intensity was very high, much higher than that of players’ efforts in 11-a-side soccer. It should be concluded that an appropriate reduction in the time players spend on the pitch during their successive efforts in one match and the consecutive tournament matches can result in reducing the decrease in the effort intensity.

Team Player Tracking Using Sensors and Signal Strength for Indoor Basketball

Wireless tracking of players for indoor team sports can provide information for both coaching assistance and individual improvement. Body worn accelerometer sensors have been used extensively to monitor and provide information such as body movements and heart rate. By also employing a beacon valuable data like player positioning and offensive play checks in the game of basketball can be provided using radio-frequency interference (RF) signal positioning techniques. Positional accuracy from a previous study using uncertainty ellipses, not yet published, shows signal variations of 3 dB having little impact on the position estimation error for a single player. The introduction of multiple moving players in the vicinity to the player worn beacon shows a variation (with no obstruction) of $\sim 1$ m or less. In depth fading studies show favorable statistical results. Previous sensor accelerometer studies show that a unique signal pattern can be used to determine if a player is bouncing the ball. Further investigation in this study shows this can also be applied to passing the ball. A prototype player tracking system was tested and confirmed wireless RF signal tracking of offensive players is viable. The results of this study can be used in design considerations for other systems employing wearable wireless sensors and beacons to estimate position and body actions for team players in basketball and potentially other sports within the indoor environment.

Injury Profile in Swedish Elite Floorball.

Background:Floorball is an indoor team sport with growing popularity worldwide characterized by rapid accelerations, decelerations, and cutting and pivoting movements. While injuries are common, there are few high-quality epidemiological investigations of floorball injuries. Therefore, the aim of this study was to determine the incidence and severity of injuries in male and female elite-level floorball players in Sweden.Hypothesis:The incidence of injuries has not decreased; female players are more vulnerable to injury than male players.Study Design:Prospective cohort study.Level of Evidence:Level 3.Methods:Twelve floorball teams (6 male, 6 female) in the Swedish premiere leagues were followed for 1 year (preseason, game season, and the entire year). The team medical staff reported injury incidence, location, type (traumatic or overuse), and severity. Differences between male and female players were analyzed using the Mann-Whitney U test.Results:The injury incidence was greater in female players during preseason (22.9 vs 7.4, P = 0.01), game season (39.5 vs 28.3, P = 0.002), as well as the whole year combined (33.9 vs 20.8, P = 0.02). The thigh was the most common injury location in male players and the ankle in female players. Overuse injuries were more common among men and were primarily back problems. Traumatic injuries were more common in women—mainly knee and ankle injuries. Most injuries were of mild severity. A greater number of anterior cruciate ligament injuries occurred in women (n = 11) than in men (n = 2).Conclusion:The injury incidence was significantly greater in female floorball players throughout the entire floorball year. Male players sustained mostly overuse injuries while female players suffered traumatic injuries. The majority of injuries in floorball were mild, irrespective of player sex.Clinical Relevance:Knowledge of the incidence and severity of floorball injuries is an essential step in the sequence of injury prevention. Future research should focus on identifying injury mechanisms and risk factors for these injuries to develop injury prevention strategies.

Jump Landing Characteristics Predict Lower Extremity Injuries in Indoor Team Sports.

The aim of this study is to investigate the predictive value of landing stability and technique to gain insight into risk factors for ankle and knee injuries in indoor team sport players. Seventy-five male and female basketball, volleyball or korfball players were screened by measuring landing stability after a single-leg jump landing and landing technique during a repeated counter movement jump by detailed 3-dimensional kinematics and kinetics. During the season 11 acute ankle injuries were reported along with 6 acute and 7 overuse knee injuries by the teams' physical therapist. Logistic regression analysis showed less landing stability in the forward and diagonal jump direction (OR 1.01-1.10, p≤0.05) in players who sustained an acute ankle injury. Furthermore landing technique with a greater ankle dorsiflexion moment increased the risk for acute ankle injury (OR 2.16, p≤0.05). A smaller knee flexion moment and greater vertical ground reaction force increased the risk of an overuse knee injury (OR 0.29 and 1.13 respectively, p≤0.05). Less one-legged landing stability and suboptimal landing technique were shown in players sustaining an acute ankle and overuse knee injury compared to healthy players. Determining both landing stability and technique may further guide injury prevention programs.

Jump Landing Characteristics Predict Lower Extremity Injuries in Indoor Team Sports.

The aim of this study is to investigate the predictive value of landing stability and technique to gain insight into risk factors for ankle and knee injuries in indoor team sport players. Seventy-five male and female basketball, volleyball or korfball players were screened by measuring landing stability after a single-leg jump landing and landing technique during a repeated counter movement jump by detailed 3-dimensional kinematics and kinetics. During the season 11 acute ankle injuries were reported along with 6 acute and 7 overuse knee injuries by the teams' physical therapist. Logistic regression analysis showed less landing stability in the forward and diagonal jump direction (OR 1.01-1.10, p≤0.05) in players who sustained an acute ankle injury. Furthermore landing technique with a greater ankle dorsiflexion moment increased the risk for acute ankle injury (OR 2.16, p≤0.05). A smaller knee flexion moment and greater vertical ground reaction force increased the risk of an overuse knee injury (OR 0.29 and 1.13 respectively, p≤0.05). Less one-legged landing stability and suboptimal landing technique were shown in players sustaining an acute ankle and overuse knee injury compared to healthy players. Determining both landing stability and technique may further guide injury prevention programs.

Sport specificity background affects the principal component structure of vertical squat jump performance of young adult female athletes

PurposeLong-term training specificity is thought to alter performance in tests evaluating strength and power production capability. The aim of the present study was to provide additional information to the limited existing knowledge concerning the possible differences of the force/time profile of squat jumping among different groups of young female athletes. MethodsOne hundred and seventy-three adult women (20.1 ± 2.8 years, 1.71 ± 0.09 m, 65.6 ± 10.3 kg, mean ± SD for age, height, and mass, respectively) engaged in track and field (TF), volleyball (VO), handball (HA), basketball (BA), and physical education students (PE) executed maximal squat jumps (SQJ) on a force plate. Pearson's correlation was used to identify the relationship between SQJ performance, the anthropometric characteristics and the biomechanical parameters. Differences concerning the biomechanical parameters among groups were investigated with analysis of variance, while the force- (FPD) or time- (TPD) dependency of SQJ execution was examined using principal components analysis (PCA). ResultsSQJ was unrelated to body height but significantly correlated with body mass (r = −0.26, p = 0.001). TF jumped higher and produced larger peak body power output compared to all the other groups (p < 0.05). All athletes were superior to PE since they performed the SQJ with a longer (p < 0.05) vertical body center of mass trajectory during the propulsion phase. PCA results revealed that TF significantly differentiated than the other groups by relying on FPD. ConclusionVarious different profiles of FPD and TPD were detected due to different sporting background in young female athletes. Since TF superiority in SQJ was relied on the larger power production and a greater FPD, female indoor team sport athletes are suggested to execute jumping exercises adopting the jumping strategies utilized by TF.

Dynamic Tracking of a 2.4GHz Waist Mounted Beacon for Indoor Basketball Player Positioning

Wireless player tracking is being considered for use within indoor team sports for coaching assistance. Few research studies exist into wireless RF signal tracking of players in indoor team sports, in particular the game of basketball. Utilising the RF signal trilateration positioning technique with three anchor nodes per quarter court, players wearing RF beacons could be tracked and their positional data recorded in real time. This study builds on a previous study conducted under static conditions by Kirkup et al. (2013). Identifying the player with the ball is also important in recording and assessing team strategies. Accelerometer sensors located on the body have been widely used to monitor the movements of the body and can potentially be used to recognize when a player is bouncing the basketball (dribbling). This paper reports the findings of using the received signal strength positioning technique with one anchor node to estimate the position of a moving basketball player towards the node and the use of a wearable triaxial accelerometer sensor to identify the person bouncing the ball. Both slow and fast game pace conditions are tested. Player position accuracy can be achieved to within 0.5m for distances less than 9m. A study of the power law variation in signal strength over distance gives an exponent n of 2.23 under moderate paced conditions with a Pearson squared correlation coefficients of r2 = 0.42. This means that 42% of the variation can be explained by the approximation. Under moving conditions, changes in the transmit antenna orientation will result in an increase of random variation in position prediction which is included in this result. The acceleration signature from a wrist sensor of the hand-ball contact process while dribbling distinctively shows ball dribbling possession. A single moving player scenario is discussed and measured results with and without the basketball demonstrate the accuracy and feasibility of the positioning and ball possession techniques. The techniques will provide valuable information for further study into multiple player and multiple beacon wireless indoor positioning.